Fluid-pressure brake



J. C. MCCUNE FLUID PRESSURE BRAKE @du 2, H928. lll

Filed ot. 19, 1926 u INVENTOR JOSE PH C. Mc CUNE ATTORNEY lill lltl

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'lllelUNlE, 0T EDGEW, PENNSYLVANIA, ASEIGNR 'llU THE WESTIltl'tl-u AmitBRAKE COMPANY, 0l? WILMERDXNG, PENNSYLVANIA, el CORPURMEOM UlliJPENNIGYLVAINJEA.. i

.'llIUID-lBJEtESSURE HEME.

application tiled october i9, 1926, eeral ll'o. 1li-neat?.

'll-This invention relates to luid pressure brakes, and moreparticularly to a brake equipment in which the brake pipe is charged vvith tluid under pressure trom the main reser-voin y ln certain types ofHuid pressure brake equipments, fluid under pressure for controlling theapplication and releasey ot the brakes is taken from` a main reservoirand is con`- trolled by the manipulation ot a brake valve device. lltthe pressure in the main reservoir should tail or become seriouslydepleted, it may prevent the operator` trom making an application ot thebrakes, when desired.

The principal object of my invention is to provide means forautomatically causing an emergency application of the brakes under theabove circuinstances.y

ln the accompanying drawing, the single ligure is a sectional view ot avalve device constructed in accordance with my invention.

Y According to the drawing, a valve device 1 is associated with a mainreservoir 2 adapt- `edfto be charged with fluid under pressure through apipe 3, by the operation ot the usual air compressor (not shown).

'lhe valve device 1 may comprise a casing containing a cut-oil valvedevice Il, avent valve device 5, a protection valve device (i, and acheclr lvalve device l. y

The cut-ott' valve device el may comprise a valve piston 9y adapted, inoneposition, to seal against a seat ring; 10 and in the oppositeposition to seal against a gasket 11.

q1lllhenthe cut-oil valve piston 9 engages the seat ring 1() the innerseated areais constantlyV subjectto fluid vat main reservoir pressure inthechamber`12 Which chamber is connected through pipe 13 `with the mainreservoir 2. The outer seated area ot the valve piston 9 is open tochamber i? at one side of `the check valve 7, the chamber 1li at theopposite side oit said check valve being connected to a main reservoirpipe 15.

The chamber 16, atthe spring side ot the cut-oil valve piston 9, isconnected to the atmosphere through port 1'7 and contains a coil spring18 which acts on said valve piston.

rllhe vent valve device 5 may comprise a piston 21 contained in pistonchamber 22 and provided with .a cylindrical extension having a chamber20, in which. is mounted a valve piston 19. t coil spring 29 is`interposed between the piston 19.

ln its position engaging the seat ring 2l, i

chamber 27, which is connected to the atmos- J pliere through passage 28ln order to prevent leakage ot fluid under pressure from chamber 22 pastthe piston 21, said piston is provided With a seat adapted to engage aseat ring` 25. lin order to ensure that the valve pistoia 1,9 willtightly engage the seat ring' 241, when piston 21 is in engagement withthe seat ring 25, a limited relative movement ot the valve piston 19 ispermitted, and. spring 29 then acts to yieldingly hold the valve pistonA19 in engagement ivith the seat ring 24.

"When the piston 21 moves away trom the position shovvn in the drawing,relative movement ot valve piston 19 is limited by a shoulder 30 on thevalve piston 19 engaging a shoulder 31 of the piston 21.

'lhe protection valve device 6 is in the form loli a valve piston 32,adapted in one position to engage a seat ring and iu the oppositeposition to seal against a gasket 34T.

When the protection valve piston 32 engages the seat ring 33, the innerseated area is subject to fluid at brali'e pipe pressure in `chamber 35,Which communicates with the usual brake pipe 36, While the outer seatedarca communicates with chamber 37 which is connected through passage ll1to chains ber 26.

rllhe valve piston 32 has chamber 38 at one side connected to theatmosphere through port 39 and is subject to the pressure of a spring-40.

ln operation, the main reservoir 2, is charged with iluid under pressurein the usual manner and main reservoir pressure builds up in chamber 12and acts against the inner seated area of the cut-oil valve piston 9.When main reservoir pressure has been increased to a'degree sullicientto overcome the pressure of the spring` 18, the cutoff valve piston 9 ismoved away from the seat ring` 10.

ls soon as the seal between the cut-otl valve aud the seat ring l() isbroken, the

piston 21 and the valveV lll llltl till 2v l 1 f- 1 1,685,855

pressure of fiuid in chamber 10 immediately becomes effective upon theentire upper area of the cut-off valvepiston 9 and quickly moves saidvalve piston to the normal operate ing position, as shown in thedrawing, in which position said valve piston 9 seals against the gasket11.

With the cut-off valve piston 9 in the normal operating position, fluidat main reser- 'voir pressure in chamber 12 flows into chamber 8, andacts against the check valve 7 to lift it and permit flow into chamber1d and thence into the main reservoir pipe 15 and to the brake valvedevice in the usual manner. Fluid underpressure in chamber 8 also flowsthrough passage 23 into chamber 22, wherein it causes the piston 21 tobe moved to the positionshown in the drawing, in whichthe valve piston19 is seated .on the seat ring 24 and thereby cuts oft communicationbetween chambers 26 and 27.

Fluid under pressure from the vmain reservoir pipe 15 is suppliedlthrough the usual brake valve device (not shown) to the brake pipe3G,,whichcommunicates with chamber 35, wherein said pressure builds upon the inner seated area of the protection valve piston 32, until thepressure becomes suiiicient to overcome the pressure ofthe opposingspring-110. The protection valve pistony 32 then starts to leave itsseat against the seat ring 33, thereby exposing the full area ofsaid-valve piston to brakevpipe pressure, which quickly moves valvepiston 32 to the position shown in the drawing, in whichV it sealsagainst the gasket 34.

The vprotection valve piston 32 being seated `against gasket 34, permitsfluid at brake pipe pressure in chamber 35 to flow into chamber 37 andthence through passage 41 into chamber 26. The valve piston 19 being'seated against seat ring 24, permits a pressure equal to that in thebrake pipe to I lbuild. up in chambers 26 and 37.

1n case the pressure of the fluid in the main reservoir 2 becomesreduced vto aY predetermined degree, through leakage from the mainreservoir atv the pipe connections, by reason of a pipe breaking, or acompressor failure, thev pressureof spring18 causes the cutoff valvepiston 9 to startv moving Vtoward the seat ring 1() and away from thegasket 11. As soon as valvepiston 9 leaves Vthe gasket 11, the fluidunder pressure in chamber4 8 flows through port/L2 into spring chamber 16 and tothe atmosphere"through port 1 7,

Athereby''causing a sudden reduction in the pressure inchamber 8i" v fanincrease in the pressureansprlng Chamber 16, which supplementstheVpressure of' spring 18 to yquickly shift the valve'piston 9 against thel seat ring 10, thereby cutting off further communication betweenthemain reservoir 2 and chamber 8.

LAfter the cut-ofi valve piston 9 has seated against the seal ring 10,the fluid under pressure in chamber 8 and chamber 22, which communicatestherewith, through passage 23, vents to the atmosphere through ports 42and port 17.

rI'he fluid under pressure being vented from chamber 22 permits thefluid at brake pipe pressure in chamber 26, acting against. the valvepiston 19 inside the scat ring 24, to cause the valve piston 19 to moveiu a downnf'arddirection, As soon as the valve piston 19 leaves the seatring 2.4i the fluid at brake pipe pressure, in chamber 26, becomeseffective over the total exposed area of the valve piston 19 and causesit to quickly move to its open position, thereby conneeting- As soon asthe seal of the protection valve 32 against gasket 34( is broken, fluidunder pressure in chamber 37 flows through ports 43 into spring chamber3S, wherein it supplements the pressure of spring 41:0 and quicklycauses the valve piston 32 to move against the seat ring 33, thuscutting olf further com munication between the brake pipe 36 connectedto chamber 35 and chamber 37 connected to the atmosphere. Fluid underpressure in spring chamber 3S is also vented to atmosphere throughv port39.

'The capacity of the vent valve Adevice 5 when open to vent. brake pipefluid from chamber 26 to atmosphere through passage 28is such as toprovide an emergency rate of reduction in thelluid under pressure in thebrakepipe 3G prior to the closing of the protection valve piston 32.This emergency rate of reduction in the brake pipe pressure produces auautomatic emergency application of the brakes in thewell known manner.

rlhe above description of the operation of my invention is based uponthe operation ofl a single car, in which case the protection valvedevice 6 and check valve device 7 serves no useful function.

In case there are two or more cars in a train, the main reservoir pipe15 and brake pipek 36 ,on each car are connected with the similar pipeson adjoining cars, so that there aretwo separatel pipe lines runningthroughout the train. With each car equipped with a main reservoir andmeans for charging the main reservoir, fluid under pressure is suppliedfrom each car to the main reservoir pipe 15. There is always thepossibility, however, that in initially charging the brake equipment onthe train, a main reservoir pressure ttl resuena suliicient to causeoperation oli the cut-oli valve device Il may be acquired on one carahead or' the other cars.

lf, in charging a train, the Cut--oit valveV device l-operates on onecar ahead ot the other cars, to supply fluid under pressure trom themain reservoir 2 to the main reservoir' pipe l5, the main reservoir pipethroughout the train will tend to be charged `from the main reservoiroi" the car on which the cut-olli' valve device first operates. lWitlithe brake valve device on the leading car in release position, fluidunder pressure will be supplied trom the main reservoir pipe to thebrake pipe, running throughout the train, and thus also charge saidbrake pipe.

Un all ot the cars oi. the train on which the cutoff valve device l hasnot operated, the chamber B is connected to atmosphere through port-s4:2 and port i7. 'lhe check valve 7, however, prevents the Huid pressurebuildingm up in chamber la, from the main reservoir pipe l5 tromilovving into chamber S and thence to atmosphere.

rlhe pressure oi spring Al0 beneath the protection valve piston 32 holdssaid valve closed against the pressure built up in chamber 35. se thaton all the cars on which the cut-eli valve 9 has not operated, iluid atbrake pipe pressure in chamber` 35 cannot be vented to atmospherethrough chamber 37, passage Lil, chambers 26 and 2i and passage 28.

`llhe fluid pressure required to shi't't the protection valve pistonaway trom the seat ring; 33 and againstthe pressure ci spring ll() issuliiciently in excess et the pressure required to shift the cut-oilvalve piston 9 away from the seat ring i() to ensure movement oit everycut-od valve d on the train to connect the main reservoir to the mainreservoir pipe l5 prior 'to the opening oit a single protection valve.

llhe check valve and protection valve device 6, therefore, are means forpreventing the loss et .fluid under pressure to the atmosphere wheninitially charging the brake equipment on. a train wherein a cut-olii'valve device ll en one car operates ahead oft a similar occurrence onthe other cars.

ln case the pressure of the :Fluid in the main reservoir 2, on any onecar in the train, lbecomes reduced sutliciently to permit the cuteiivalve device 4 on that car to operate, an emergency rate of reductionwill be produced in the brake pipe 36 in the same manner as heretoforedescribed for a single car. The brake pipe being continuous throughoutthe train, the emergency rate of reduction will be transmitted to thevalve device on each car, which will automatically apply the brakes.

Having new described my invention, what ln claim as new and desire tosecure b v Letters Patent, is

l. ln a iiuid pressure brake, the combination with a main reservoir, amain reservoir pipe, and a brake pipe, oi a cut-Ott valve deviceeperated upon a predetermined reduction in pressure in the mainreservoir for cutting oli' con'imunication from the main reservoir tothe main reservoir pipe and a vent valve device controlled by saidcut-off valve device and operated by venting' fluid from one sidethereoil for venting fluid from the brake pipe to eii'ect an applicationof the brakes.

2. in a iiuid pressure brake, the combination. with a main reservoir andbrake pipe, ot a vent valve device operated upon a predeterminedreduction in pressure in the main reservoir iter ventingl tluid from thebrake pipe and a valve device for cutting oli communica tion trom thebrake pipe to said vent valve device until the brake pipe pressure b asbeen increased to a predetermined degree.

lu a fluid pressure brake, the combination with a main reservoir, a mainreservoir pipe, and a brake pipe, of a vent Valve device 'for ventingliuid from the brake pipe to eli'ect an application oi the brakes, acut-oil' valve device operated. upon a predetermined. reduction in brakepipe pressure ier operating said vent valve device `to opencommunication through Whi ch iiuid is vented from the brake pipe, and aprotection valve device for cutting oli' communication from the brakepipe to said vent valve device until the brake pipe pressure has beenincreased to a predeter mined degree.

4t. lln a fluid pressure brake, the combination With a main reservoirand a brake pipe, ot a vent valve device normally subject to theopposing pressures oit the brake pipe and main reservoir, and a valvedevice operated upon a reduction in pressure in the main 'reservoir torventing iluid from the main reservoir side ot said vent valve device, tothereby operate said vent valve device to vent liuid from the brakepipe.

ln testimony Where of l have hereunto set my hand.

JOSEPH C. MCCUNE.

tillV lti mit

